Typewriting machine



June 12, 1928.

-A. G. .F. .KUROWSKI TYPEWRITING MACHINE Filed March '7, 1924 2 Sheets-Sheet l June 12, 1928. 1,673,289

' A. G. F. KUROWSKI TYPEWRITING MACHINE Filed llarch v, 1924 2 Sheets-Sheet 2 Alb/we Patented June 12, 1928.

ALFRED G. F. KUROWSKI, OF BROOKLYN, NEW

LIOTT FISHER COMPANY, OF NEW YORK, N.

myrnwmrme MACHINE.

YORK, ASSIGNOB T0 ominawoon n1.- Y., a conronanon or DELAWARE.

Application filed March 7, 1924. Serial No. 897,470.

This invention relates to typewriting machines of the portable class, in which, for

compactness and lightness, it is usualto employ three rows of keys, with prov sion 5 for operating three types by any key.

An object of the invention is to so arrange the parts of a front-strike two-shift typewriting machine, having forty-two typebars and keys to correspond arranged in 10 four banks, that they will occupy a minimum of space without impairment of the efliciency of the machine.

Another object is to so connect the keylevers and type-bars that the movement of the key-levers is transmitted to the typebars with the leverage increasing gradually toward the side bars, thereby to compensate for the unfavorable position of said bars.

Another object is to so arrange the universal bar with respect to the type-bars, and to so connect the keys and type-bars, that the type-bars will engage the universal bar at the moment of greatest acceleration,

while the leverage between the keys and type-bars will steadily and rapidly increase from the moment of impact with the universal bar to the end of the stroke;

Other features and advantages will hereinafter appear.

In the accompanying drawings,

Figure 1 is a longitudinal Vertical section.

Figure 2 is a partial plan view.

Figure 3 is a View of a portion of the machine looking from the front, with parts in section.

Figures 4 and 5 are diagrammatic views, the former of a center key, and the latter of a side key, showing the keys in printing position and in rest position.

In the present embodiment of the invention, the improved typewriting machine comprises a main frame, composed of a rear plate 1, side plates 2 and 3, and a front plate 4, said front plate being slotted vertically, as shown at 5, to form a front comb for the key-levers 7. The key-levers are forty-two in number, to correspond with the type-bars, and they are pivotally mounted at their rear ends on a fulcrum rod 6. The plate 1, aforementioned, is transversely slotted on its under side at regular intervals, to receive the rear ends of the key-levers 7, and said plate is also slotted longitudinally to receive the fulcrum rod 6 on which the key-levers are pivoted. The fulcrumthe springs. The plate is a the amount of rod slot intersects all the transverse slots for the key-levers, and each key-lever has a substantially U-shaped slot in its upper edge for receiving the fulcrum rod. The key-levers are inserted in the transverse slots from below, as shown, and they are held in engagement with the fulcrum rod spring mechanism to be described.

Said mechanism comprises a coil spring 8 for each key-lever, each spring being connected at one end to the' lever, as shown in Figure 1, and at the other to a tension plate 9. The tension plate 10, which are secured the rear plate 1 in any suitable manner, as, for instance, b screws as shown, and said plate extends from side to side of the machine frame, and is adjustable at its free edge, to simultaneously var the tension of d usted vertically at its free edge b means of screws 11. These screws are tlireaded through bosses 12 on the tension plate into engagement with the top of the plate 1, and they are held in adjusted position by means of lock-nuts 13. Each key-lever 7 extends beyond the comb l, and at its free end it is provided with an upturned portion carrying a key 14, the keys being arranged in four banks as shown. The typing system, which includes a platen 15, a type-bar rest 17, and a type-bar segment 16 carrying forty-two type-bars 20, is arranged above the key-levers. The t pebars are pivoted on a fulcrum rod 19 eld in the segment in the usual manner. The type-bars are of the usual construction, each having an open slot to hook over the fulcrum rod 19. -Each type-bar is provided with an arm or heel 21 by means of which it is connected to the corresponding key lever, and the bars strike against an anvil 22 on the segment, the usual type-bar guide 23 being provided for insuring the correct striking of the type on'the platen. In the usual construction, the typing assembly is 9 is hingedto leaves to the rear face of so arranged that the type-bars are substantially horizontal when in rest position, and are substantially vertical when in printing position. The provision of forty-two type- I bars, necessary in a two-shift machine, necessitates that the bars be longer.

Were the typing assembly arranged in the ordinary manner, the height would be increased by extra length of type-bar, as would also the depth from front to rear.

v the type-bar without increase in the eight.

' in parallel relation,

nect the arms to the type To compensate for the increased len h of g;- depthof the machine, the typing assem- 1s th at the type-bar rest is brought to sub stantially the level of the platen, the segment being ositioned at the lowest part in the assem ly, and well below the typebar rest. This tilting of the assembly materially reduces the distance between the bottom of the se ent and the top of the machine, that'is t e plane at the top of the platen and type-bar rest.

The vertical height of the machine is still further reduced by offsetting the key-leversdownwardl intermediate their ends, as indicated at so that they will dip beneath the segment. The, levers are sufficiently offset to pass beneath the segment and the connecting mechanism between the type-bars .and the key-levers.

The key-levers'are connected to the corresponding type-bars by connections, each of which includes a toggle. A series of hellcrank levers 25 is mounted on a common support 24 held transversely of the frame near the front thereof. This support is longitudinally slotted on its upper face to receive a fulcrum rod 26, and the support is provided with a series of transverse slots on its upper face, intersecting the longitudinal slot, the transverse slots being designed to receive the bell-cranks which are pivoted on the fulcrum rod 26. The transmitting arm of each bell-crank is connected to the operating arm or heel of the adjacent type-bar by means of a link 27, each link being pivoted at one end to the arm of the bar and at the other to the outer end of the transniittinv arm of the bell-crank. The other, arm of each bell-crank is longitudinally slotted, as indicated at 28, each slot being designed to receive a laterally extending pin 29 on the adjacent key-lever 7 The ins 29 are shouldered, and they are slidab e in the slots 28 of the bell-cranks. Each lever has a depending lug 31 with which the pin 29 is ened, and it will be noticed that all of the ey-levers arch.v above the common support 24 for the bell-cranks.

The bell-cranks are. pivoted parallel with the ke -levers, and the transmitting armsof the be -cranks are bent laterally inward on each side of the center of the machine, and at an angle such that they are in approximate alignment with thelinks 27 whic conba,rs. Referring toFigure 1, it will be seen that the key levers are of considerable length, and are pivoted well up at the rear of the machine, at about the lowest part of the segment. The levers are arranged alongside each other that the connection between each side typebar and its key-lever during the movement tilted or inclined to an extent such restoring the side key-levers.

and they are so spaced" of the key and bar moves in a vertical plane, which is perpendicular to the fulcrum of the type-bar. With this arrangement, when a key is depressed, the pull upon the type-bar is substantially perpendicular to the axis upon which it swings, and binding and friction-are eliminated.

The link 27 forms one member of what is, in effect, a toggle joint. The other member may be considered as the transmitting arm 25 of the bell-crank or as the operating arm of the type-bar. Thus, each connection between a key-lever 7 and a type-bar 20 includes a toggle joint. Referring to Figures 4 and 5, it will be noticed that in the rest position of the type-bars, the toggle is broken, the members being just out of alignment. This relation is maintained for all the type-bars, the angle between the links 27 and the transmitting arms 25 being substantially the same throughout the assembly. To maintain this relation, the transmitting arms 25 of the bell-cranks must rise toward the sides of the machine, since the fulcrums 19 of the type-bars are rising. The rise of the transmitting arms 25 does not, however, equal the rise of the type-bar fulcrums 19', and the angle between the respective typebar operating arms 21 and the connections 25-27 between the keys to which they are attached gradually becomes greater toward the sides of the machine. At the middle of the assembly, these angles are acute, and, at the sides,.while they are still acute when the type-bars-are in rest position, they are conslderably wider than at the center.

The more nearly the angle between the length of" the type-bar operating arm 21 vposition of the type-bars at the sides is com ensated for.

I e ty -bars 20 at the sides are less subject to t e action of gravity, swinging, as they do, through a plane inclined to the horizontal at approximately 60. Hence, the gravitative reaction which assists in the resto'ration'of the middle bars to rest position is reduced to such an extent that the side bars are sluggish in movement. This tendency to sluggi, ness is usuallycorrected by the provision 'of stronger 5 rings 8 for reater stress is required to operate the sidebars 20 because of their unfavorable position, as above mentioned, and by providing the key-levers 14 with stronger springs, the stress required to operate the keys is further increased, but the leverage between the key-levers and the type-bars is gradually increased from the center toward the sides of the machine, by gradually widening the angle between the type-bar operating arms 21 and the toggles 2725, so that a given pressure on the side keys would be more efiectively applied in the swing of the type-bar than at the middle bar. The link ends of the transmitting arms 25 gradually fall below the fulcrums of the type-bars towards the sides of the system.

The transmitting arms 25 of the bellcranks are raised by lengthening them, as indicated in Figures 3, 4 and 5, and also by making the angle between the elbow portions of the respective bell-cranks more acute. Said raising of the transmitting .arms 25 increases their stroke, and, in order that the dip of the keys 14 may be uniform, the operating arms or heels 21 of the side keys are lengthened to compensate for the increased stroke of the side bars. -If-the lengthening of the operating arms or heels 21 were gradual from the center type-bars to the side bars, each bar would differ from all the remaining bars. This, however, is not essential, since the difference in the width of theangle between the operating armor heel 21 and the toggle 25-27 of any particular type-bar and the adjacent bar is slight. For this reason the bars 20 are divided into three sets, the bars of each set being of the same length. The middle set or series is composed of twenty-two bars, eleven on each side of the center. The second set comprises six bars on each side of the middle set, and the third set comprises eight bars, four at each side, as

clearly shown in Figure 3.

In the present invention, the universal bar 32 controls the carriage-feeding in the usual manner, and is so positioned with respect to the type-bars that it will be engaged by the bars at the moment of their greatest ac celeration, and at the moment when the toggle 2527, which is a part of the connection between the type-bar 20 and the key 14, is passing from a right angle to an obtuse angle, that is, when the members of the toggle are moving into alignment. At such movement, the stress upon the key commences to act u on thekey with a: leverage h increasing stea ily and rapidly to the end of the printing stroke. Referring'to Figure 1, it will be noticed that each type-bar has an extension 33 on its rear edge and ad jacent the fulcrum, which will engage the universal 'bar 32 when the type-bar is substantially vertical. At this moment the angle between the operating arm or heel 21 of the type-bar and the adjacent member of the toggle, that is, the link 27,-is a right angle. Further movement of the key-lever associated therewith tends to enlarge the same, that is to bring the type-bar fulcrum 19, the end of the operating arm 21, and the end of the transmitting arm 25 of the bellcrank towards astraight line intersection of the three pivotal points. During the movement of the type-bar, from the time the type-bar starts from rest position until it attains the position of Figure 1, thereis acceleration, that is, increased speed with less power. When the. parts attain the position of Figure 1, the acceleration of the typebar is at ment there is relative decrease in speed, with increase in power. The arrangement is such that at its start until it assumes a vertical position, the type-bar is not burdened in any manner by operating other parts. Thus the wholetouch or impact at the key may be utilized to raise and set the typebar in motion before it takes up and operates the escapement device.

The type-bars20 are assisted in their initial or starting movement from rest position by the connections 29 between the keylevers l4 and the bell-cranks 25. The arms its highest, and with further move are arranged alike, each in such manner that the slot 28 inclines downwardly and rearwardly, presentingthus an inclined or cam surface to the pin 29 which co-operates therewith. When a key is, depressed, the pin 29 slides along the slot wall 28 with a. camming action that provides for an'easy start.

By increasing the leverage between the key-levers and type-bars at the sides of the machine, and by making such increase gradual, the same amount of pressure on any selected key will produce like results at the attached type-bar throughout the assembly. The touch is thus made uniform, and equally alike for all of the keys.

Variations may be resorted to within the scope of the invention, and portions of the improvements may be used without others.

Having thus described my invention, I claim:

1. In a typewriting machine, the combination with type-bars and keys for operating the same, of connections between the keys and bars, said connections includin bell-cranks-pivoted on a common axis, an

'nks connecting the transmitting arms of the bell-cranks to the bars, the link ends of said transmittin arms being above the fulcrums of the middle ba'rs'and gradually fallin below the fulcrums toward the sides,

where y to widen I the angle between the,

bell-cranks,

and links connecting the transion mittin arms of the bell-cranks t0 the bars,

the lin ends of said transmitting arms being above the fulcrums of the middle bars and gradually falling below the fulcrums to ward the sides, whereby to widen the angle between the type-bars and the links.

3. In a typewriting machine, the combination with type-bars and keys for operating the same, of connections between the keys and bars, said connections including bell-cranks pivoted on a comon axis, and links connecting the transmitting arms of the bell-cranks with the type-bars, the transmitting arms of the bell-cranksrising gradually toward the sides of the machine, but

and bars, said connections including bell cranks pivoted on a common axis, and links connecting the transmitting arms of the bell-cranks with the type-bars, the transmitting arms of the bell-cranks rising toward the sides ofthe machine to follow the rise of the type-bar. fulcrums, but gradually falling below said fulcrums to increase the angle between the ty e-bars and the links.

ALFRED F. KUROWSKI. 

